THE PRIOR ART
The present invention broadly relates to baghouse filtration systems. Specifically, the present invention is a Translational Press and Mandrel Apparatus for Straightening Baghouse cages. Art pertinent to the subject matter of the present invention can be found in U.S. Patent Classes 29 and 55.
Baghouses are employed to filter particulates from air expelled by various commercial processes. Some processes employ baghouses to remove hazardous wastes before venting to the atmosphere. Other processes use baghouses to gather output product.
Most modern baghouses employ a stainless steel skeletal framework, commonly referred to as a cage, to support filter bags. Together the cage and bag form a cartridge. Various mounting systems are used to anchor these cartridges in baghouse structures. Generally speaking, the cartridges are mounted to a tube sheet which is a flat plate with a plurality of cartridge receptive orifices defined in it. The cartridges may be clamped in place. Alternatively, a series of indents or notches defined in a flange around the opening mate with grooves or ribs defined in a shroud on the open end of the cage to hold the cartridge in place. The tube sheet is mounted in the baghouse in such a manner that it separates the input gases from the output gases. Gases to be filtered pass though the bags in one direction or the other, collecting material on the outside or the inside of the bag.
Innumerable patents are directed to baghouse configurations. Birkholz, U.S. Pat. No. 1,821,202, discloses a renewable capsule filter which employs a baghouse structure having a mesh frame. More conventional, modern baghouses are disclosed in several U.S. Patents. Dobyns, U.S. Pat. No. 4,976,756, discloses a dust collector with a hinged roof to facilitate cleaning and use. Heffernan, U.S. Pat. No. 4,309,200,discloses a baghouse with a collapsible filter bag assembly.
Some U.S. Patents speak directly to filter structures and the connections employed to secure the cartridge to the tube sheet. De Martino, U.S. Pat. No. 4,256,473, discloses a cylindrical collar unit used to attach a bag frame to the permanent baghouse structure. Gravley, U.S. Pat. No. 3,937,621, discloses a filter bag cuff. It is basically a ring folded within the fabric of the bag and stitched into place. Reinauer, U.S. Pat. No. 4,073,632, discloses a structure for mounting bags. This structure uses a semirigid bag with an integral framework. This patent discloses two end caps, one which allows the entrance of air and the other which supports the distant end of the bag. Miller, U.S. Pat. No. 4,042,356, discloses a baghouse cell plate and filter bag attachment. Here a structure extends outward from the baghouse cell plate with a grove in it for accepting the upper lip of a filter bag. U.S. Pat. No. 4,424,070 issued to Robinson Jan. 3, 1984, discloses a dust collecting filter cartridge and attachment structure. The attachment structure is an adapter that uses a rubber clamp to mate dissimilarly sized cartridges and tube sheets.
Other patents speaking to baghouse filter structures include: Schaltenbrand, U.S. Pat. No. 4,157,901; Noland, U.S. Pat. No. 4,194,894; Bergquist, U.S. Pat. No. 4,257,790; Brown, U.S. Pat. No. 4,277,874; Nijhawan, U.S. Pat. No. 4,435,197; Reier, U.S Pat. No. 4,618,353; Price, U.S. Pat. No. 5,017,200
U.S. Pat. No. 5,095,607 issued to Simon on Mar. 17, 1992, discloses a tool for securing baghouse filters. It employs a tapered head to expand the open end flange of a baghouse filter cartridge the to facilitate inserting it into the tube sheet or other framework.
Various means are employed to clear the material from the bags in the baghouse. For example, Bundy, U.S. Pat. No. 4,113,449 discloses a two step process. First, the pressure of the gases flowing through the bags is reduced. Next the bags are blasted with high pressure gas to dislodge collected particles. Another method uses vibration. However, over time the bags become so heavily clogged with material that they must be replaced.
The first step in replacing the bags is removal of the cages mounting the filtration bags from the baghouse. Once removed from the baghouse, the bags are stripped from the cages. Previously, bent or damaged cages were generally discarded as scrap metal. Cages are often bent during the stripping process. The value of a cage as scrap metal, in comparison to the cost of a new cage, is minuscule. Welds holding the cages together are often destroyed due to continual exposure to vibration in the baghouse. Welds may also be broken during removal from the bag house or during subsequent handling. Hence, it is desirous to repair damaged cages during a baghouse retrofit. Particularly, it is desirable to straighten bent cages rather than discard them as scrap metal.